Method to indicate filter replacement in a refrigerant recovery and recharge device

ABSTRACT

A refrigerant recovery and recharge device is configured to be connected to refrigeration equipment. The device includes a filter configured to filter refrigerant and removal contaminants in recovered refrigerant. The filter includes a fuse configured to indicate when the filter should be replaced.

This invention related to a method to indicate filter replacement in a refrigerant recovery and recharge device.

STATE OF THE ART

US patent publication numbered 20080000240 discloses a refrigerant filter change indication method. For the purpose of indicating that the filter d checking the life of the filter the volumetric flow of refrigerant in the filter is checked. When the amount of refrigerant flowing through the filter has crossed a certain limit it is indicated that the filter should be replaced.

ADVANTAGES OF THE INVENTION

The method to indicate filter replacement in a refrigerant recovery and recharge device according to the independent claims have the following advantages.

BRIEF DESCRIPTION OF THE ACCOMPANY DRAWINGS

Different modes of the invention are disclosed in detail in the description and illustrated in the accompanying drawing:

FIG. 1 illustrates a Refrigerant recovery and recharge device with various components; and

FIG. 2 illustrates a block diagram representing the devices involved in indicating filter replacement.

DETAILED DESCRIPTION

FIG. 1 illustrates a refrigerant recovery and recharge device 10 with various components. While recovering and recharging refrigerant the refrigerant recovery and recharge device 10 is connected to a refrigeration equipment 12. The refrigerant recovery and recharge device 10 comprises at least a valve block 14 which establishes a connection between the refrigeration equipment 12 and the refrigerant recovery and recharge device 10. A filter 16 is present in the refrigerant recovery and recharge device 10. The filter 16 helps to trap moisture or other particulate matter which may be present in the refrigerant while recovering the refrigerant from the refrigeration equipment 12. The refrigerant then passes through a compressor 18 and is stored in a refrigerant storage tank 20. Refrigerant storage tank 20 is placed on a load cell 22 to check the weight of the refrigerant recovered. The refrigerant recovery and recharge device 10 has a controller 24 means which is used to electronically control the working of the valve block 14, the filter 16, the compressor 18 and the refrigerant storage tank 20. In FIG. 1 the darker connection between the controller 24 and the other components indicates that data communication takes place between the controller and the other components of the refrigerant recovery and recharge device 10.

In refrigerant recovery and recharge devices filters are employed for the removal of moisture, particulate matter and the like. The removal of moisture, particulate matter and the like is done when the refrigerant passes through the filter. After many cycles of refrigerant recovery from the refrigeration equipment it is observed that the filter becomes less effective which may be because the filter element may get saturated and non-functional. The saturation and non-functionality of the filter may result in particulate matter being conveyed to the remaining components of the refrigerant recovery and recharge device. This may in turn effect the working of those components and reduce the life of the components.

Hence there is need that the filter should be replaced periodically when the effectiveness of the filter reduces beyond a certain limit. However the filter should be randomly replaced. In certain cases it is possible that the filter element is replaced before the filter element gets saturated. This would increase the cost of working refrigerant recovery and recharge device. Thus it is essential that the filter be replaced only after a certain amount of refrigerant has passed through the filter.

In conventional devices which measure the amount of refrigerant that has passed through the filter. Volumetric flow of the refrigerant through the filter may be measured using a mass flow meter which is used to measure the volume of the refrigerant that flows through the filter. Once certain volume of the refrigerant has passed through the filter the refrigerant recovery and recharge device indicates that the filter should be replaced. The indication may be audio or visual or the like indication.

In accordance with this invention there is provided a filter for use in a refrigerant recovery and recharge device and a method for indicating that the filter should be replaced. FIG. 2 illustrates a block diagram representing the devices involved in indicating filter replacement. The filter 16 comprises a fuse 26 which is used to check if the filter needs to be replaced. The controller 24 is adapted to send a signal to a fuse blow circuit 28. The fuse blow circuit 28 may be external as shown in FIG. 2 or may be integral part of the controller 24. The fuse blow circuit 28 renders the fuse 26 inoperative when the signal is received from the controller 24. When the fuse 26 is rendered inoperative an audio and/or visual indication indicating that the filter 16 should be replaced is provided in the refrigerant recharge and recovery device 10.

The working of the filter and the method of indicating filter replacement will be explained hereinafter. In one embodiment of the invention the amount of refrigerant that has passed through the filter 16 is determined by the weight of the refrigerant storage tank 20. A load cell 22 is normally used to measure the weight of the refrigerant that is recovered. Depending on the weight of the refrigerant recovered, the amount of refrigerant flowing through the filter 16 is monitored. If the amount of refrigerant recovered either over one cycle of recovery or many cycles of recovery is higher than a set limit, then this indication is provided to the controller in the refrigerant recovery and recharge device 10. The controller 24 in the refrigerant recovery and recharge device 10 sends a signal to the fuse blow circuit 28 to render the fuse 26 inoperative. Before continuing the recovery in the next cycle the controller 24 in the refrigerant recovery and recharge device 10 checks if the fuse 26 is intact. If the controller 24 encounters that the fuse 26 is blown out then controller 24 not only provides an indication of the same but also completely stops the working of the refrigerant recovery and recharge device 10. The indication to replace the filter may be in the form of a warning light glowing on the front panel of the refrigerant recovery and recharge device 10 with a audio beep type warning or a voice command indicating that the filter should be replaced.

The working of the refrigerant recovery and recharge device 10 is resumed only after a new filter 16 is fitted into the refrigerant recovery and recharge device 10. Even after the new filter 16 is installed in the refrigerant recovery and recharge device 10 the controller 24 checks if the fuse 26 is intact. If the fuse 26 is not intact it is an indication that the filter 16 being used does not match the requirement of the refrigerant recovery and recharge device 10 and it should be replaced. In such a case the working of the refrigerant recovery and recharge device 10 remains stopped or suspended. When the controller 24 recognizes that the fuse 26 is present it is an indication that the filter 16 being installed is new.

Thus the controller 24 not only provides an indication when the filter should be replaced but also an indication if the filter 16 being used is in proper working condition to be effective for filtering contaminants from the refrigerant.

In accordance with another embodiment of this invention there is also provided a mass flow meter which measures the mass of the refrigerant that flows through the filter. Based on the reading of the amount of refrigerant flowing through the filter an indication if the filter 16 should be replaced or not is provided by the controller in the refrigerant recovery and recharge device 10.

It should be understood that the embodiment of the invention as shown in the diagram is only illustrative and does not restrict the scope of this invention. The scope is clearly defined in the claims and the specification is used to explain the working of the invention. 

1. A method to indicate filter replacement in a refrigerant recovery and recharge device comprising: (i) connecting said refrigerant recovery and recharge device to refrigeration equipment through a valve block; (ii) recovering refrigerant from said refrigeration equipment, wherein said refrigerant flows through a filter during recovery; (iii) measuring an amount of refrigerant recovered that flows through said filter; (iv) rendering the filter inoperative if the amount of refrigerant recovered exceeds a limit; and (v) indicating that said filter needs replacement when said filter is rendered inoperative.
 2. The method as claimed in claim 1, wherein rendering the filter inoperative includes making a fuse inoperative.
 3. The method as claimed in claim 2, wherein said refrigerant recovery and recharge device is rendered inoperative by making the fuse inoperative.
 4. The method as claimed in claim 3, wherein said refrigerant recovery and recharge device is operative only when said inoperative filter is replaced with a new filter with a new fuse.
 5. A refrigerant recovery and recharge device configured to be connected to refrigeration equipment, said device comprising: a valve block configured to establish connection between the refrigerant recovery and recharge device and the refrigeration equipment and to recover refrigerant; a compressor configured to compress said recovered refrigerant; a refrigerant storage tank configured to store said compressed recovered refrigerant; a controller configured to control the working of said valve block, said compressor and said refrigerant storage tank; and a filter configured to filter said refrigerant and removal contaminants in said recovered refrigerant, said filter including a fuse configured to indicate when the filter needs replacement.
 6. The device as claimed in claim 5, wherein said device further comprises a load cell configured to measure a weight of the refrigerant recovered from said refrigeration equipment, by said refrigerant recovery and recharge device.
 7. The device as claimed in claim 6, wherein filter replacement indication is provided according to an amount of refrigerant recovered.
 8. The device as claimed in claim 7, further comprising a flow meter configured to determine an amount of refrigerant flowing through said filter.
 9. The device as claimed in claim 8, wherein filter replacement indication is provided according to a weight of refrigerant recovered.
 10. The device as claimed in claim 5, wherein said device further comprises a filter replacement indicator, said filter replacement indicator being one of an audio indicator or a visual indicator. 